1. Field of the Invention
The present invention relates to display devices such as liquid crystal display devices, and particularly to an active-matrix display device.
2. Description of the Background Art
These days, display devices, such as liquid crystal display devices, are used in a wide field of application from home TVs to industrial displays.
For example, a configuration of a liquid crystal display device is roughly classified into a liquid crystal panel and a drive unit that drives the liquid crystal panel. A conventional drive unit includes a plurality of image-signal-line drive circuits, a plurality of scanning line drive circuits, and a timing controller that serves as a control circuit for driving these drive circuits.
Each image-signal-line drive circuit is an integrated circuit for driving the image signal lines of the liquid crystal panel. The plurality of integrated circuits are used to drive all the image signal lines of the liquid crystal panel. Similarly, each scanning line drive circuit is an integrated circuit for driving the scanning lines of the liquid crystal panel. The plurality of integrated circuits are used to drive all the scanning lines of the liquid crystal panel.
The timing controller receives image data, control reference signals that serve as a reference for controlling the image-signal-line drive circuit and the scanning line drive circuit, and a dot clock (DCLK) that serves as a reference for performing processes. The above-described control reference signals include signals such as a horizontal synchronizing signal (HD) used as a reference signal for horizontal synchronization of the liquid crystal panel, a vertical synchronizing signal (VD) used as a reference signal for vertical synchronization of the liquid crystal panel, and a data enable signal (DENA) that indicates a period in which the image data is valid.
These days, as disclosed in Japanese Patent Application Laid-Open No. 2010-190932, an image-signal-line drive circuit in which a timing controller is installed (incorporated) has been developed. Since such an image-signal-line drive circuit eliminates the need for a circuit substrate for the timing controller, it is possible to reduce material costs. This results in achievement of low pricing of liquid crystal display devices.
The liquid crystal display device is provided with the plurality of image-signal-line drive circuits in each of which the timing controller is incorporated. One timing controller in itself, however, will suffice. Accordingly, one of the plurality of image-signal-line drive circuits is used in master mode. The remaining image-signal-line drive circuit is used in slave mode. More specifically, the master mode image-signal-line drive circuit operates based on its timing controller. The slave mode image-signal-line drive circuit receives the control signal from the timing controller of the master mode image-signal-line drive circuit and operates. In this case, it is possible to reduce power consumption by suspending the timing controller of the slave mode image-signal-line drive circuit.